Imaging apparatus and distance measurement system

ABSTRACT

[Object] To uniformly produce electric fields when performing thinning processing of generating electric fields in only some of a plurality of pixels. 
     [Solution] There is provided an imaging apparatus including: a pair of electric field application electrodes and a pair of electric charge extraction electrodes provided to each of a plurality of pixels; and a voltage application section configured to apply voltage between a first electrode that is one of the pair of electric field application electrodes of a first pixel and a second electrode that is one of the pair of electric field application electrodes of a second pixel when pixel combination is performed, and produce an electric field across the first pixel and the second pixel.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. § 371 as a U.S.National Stage Entry of International Application No. PCT/JP2017/007216,filed in the Japanese Patent Office as a Receiving Office on Feb. 24,2017, which claims priority to U.S. Patent Application No. 62/303,506,filed Mar. 4, 2016, each of which is hereby incorporated by reference inits entirety.

TECHNICAL FIELD

The present disclosure relates to an imaging apparatus and a distancemeasurement system.

BACKGROUND ART

In recent years, time of flight (ToF) sensors or the like have been usedas sensors that measure the distance to targets. For example, PatentLiterature 1 below describes a ToF sensor that uses a pair of electrodesto generate an electric field.

CITATION LIST

Patent Literature

Patent Literature 1: JP 2011-86904A

DISCLOSURE OF INVENTION

Technical Problem

However, the technology described in Patent Literature 1 has the problemthat the use of a pair of electrodes to generate an electric field ineach of a plurality of pixels included in the ToF sensor increaseselectric power consumption. In contrast, when thinning processing ofgenerating electric fields in only some of the plurality of pixels isperformed, the electric fields are biased. It is difficult to uniformlygenerate electric fields in pixel regions.

It has been then required to uniformly produce electric fields whenperforming thinning processing of generating electric fields in onlysome of a plurality of pixels.

Solution to Problem

According to the present disclosure, there is provided an imagingapparatus including: a pair of electric field application electrodes anda pair of electric charge extraction electrodes provided to each of aplurality of pixels; and a voltage application section configured toapply voltage between a first electrode that is one of the pair ofelectric field application electrodes of a first pixel and a secondelectrode that is one of the pair of electric field applicationelectrodes of a second pixel when pixel combination is performed, andproduce an electric field across the first pixel and the second pixel.

In addition, according to the present disclosure, there is provided adistance measurement system including: a floodlight apparatus configuredto floodlight a target with light; an imaging apparatus configured toreceive light reflected by the target; and a control apparatusconfigured to control the floodlight apparatus and the imagingapparatus. The imaging apparatus includes a pair of electric fieldapplication electrodes and a pair of electric charge extractionelectrodes provided to each of a plurality of pixels, and a voltageapplication section configured to apply voltage between a firstelectrode that is one of the pair of electric field applicationelectrodes of a first pixel and a second electrode that is one of thepair of electric field application electrodes of a second pixel whenpixel combination is performed, and produce an electric field across thefirst pixel and the second pixel.

Advantageous Effects of Invention

According to the present disclosure, it is possible to uniformly produceelectric fields when performing thinning processing of generatingelectric fields in only some of a plurality of pixels.

Note that the effects described above are not necessarily limitative.With or in the place of the above effects, there may be achieved any oneof the effects described in this specification or other effects that maybe grasped from this specification.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic cross-sectional view illustrating a ToF sensorthat is an imaging apparatus 1000 according to an embodiment of thepresent disclosure, and has a CAPD structure.

FIG. 2 is a schematic diagram illustrating both the schematiccross-sectional view illustrated in FIG. 1 and a top plan view of theToF sensor.

FIG. 3 is a plan view illustrating an example in which two pixels arecombined in a case where pixel combination is performed with CAPDpixels.

FIG. 4 is a plan view illustrating an example in which voltage isapplied to a p-type diffusion layer of one of two adjacent pixels.

FIG. 5 is a plan view illustrating pixel combination according to anembodiment of the present disclosure.

FIG. 6A is a plan view illustrating a variation of arrangement ofpixels.

FIG. 6B is a plan view illustrating a variation of the arrangement ofpixels.

FIG. 6C is a plan view illustrating a variation of the arrangement ofpixels.

FIG. 7 is a schematic diagram illustrating an example in which pixelcombination is performed on a region (2×2-pixel region) that includestwo pixels in a vertical direction and two pixels in a horizontaldirection.

FIG. 8 is a schematic diagram for describing driving of a pixel.

FIG. 9 is a schematic diagram for describing the driving of a pixel, andillustrates a configuration of a case where electrodes diagonallypositioned in two adjacent pixels are driven.

FIG. 10 is a schematic diagram illustrating an example in which a switchis provided to produce an electric field pixel in an oblique directionlike FIG. 9 when pixel combination is performed.

FIG. 11 is a schematic diagram illustrating a configuration of adistance measurement system including an imaging apparatus according tothe present embodiment.

FIG. 12 is a block diagram illustrating a schematic configurationexample of a vehicle control system that is an example of a mobileobject control system to which the technology according to the presentdisclosure can be applied.

FIG. 13 is a schematic diagram illustrating an example of installationpositions of an imaging section and a vehicle outside informationdetecting section.

MODE(S) FOR CARRYING OUT THE INVENTION

Hereinafter, (a) preferred embodiment(s) of the present disclosure willbe described in detail with reference to the appended drawings. Notethat, in this specification and the appended drawings, structuralelements that have substantially the same function and structure aredenoted with the same reference numerals, and repeated explanation ofthese structural elements is omitted.

Note that the description will be made in the following order.

-   1. Prerequisite Technology-   2. Example of Pixel Combination according to Present Embodiment-   3. Regarding Driving of Pixel-   4. Configuration Example of Distance Measurement System according to    Present Embodiment-   5. Application Examples    1. Prerequisite Technology

In the case where pixel combination is performed in a ToF sensor havinga CAPD structure, voltage is applied to a pair of electric fieldapplication electrodes in a plurality of pixel regions and electriccharges are extracted from a pair of electric charge extractionelectrodes. This makes it possible to acquire the electric current valuecorresponding to an electric charge excited by light. At this time,performing pixel combination decreases electric field applicationelectrodes to which voltage is applied, so that it is possible to reduceelectric power consumption.

FIG. 1 is a schematic cross-sectional view illustrating a ToF sensor1000 that is an imaging apparatus according to an embodiment of thepresent disclosure, and has a CAPD structure. The base layer of the ToFsensor 1000 includes an epitaxial layer 10 of silicon. As illustrated inFIG. 1, when light 60 is incident on the ToF sensor 1000, electrons 70are excited. A power supply 90 produces electric fields 105 for movingthe electrons 70 that are excited by the light 60. In addition, thepower supply 100 generates voltage for extracting the electric chargesof the excited electrons. Among the two electrodes at both ends of thepower supply 90, an electrode Mix0 is connected to a p-type diffusionlayer 20, and an electrode Mix1 is connected to a p-type diffusion layer30. In addition, among the two electrodes at both ends of the powersupply 100, an electrode Collector0 is connected to an n-type diffusionlayer 40, and an electrode Collector1 is connected to an n-typediffusion layer 50.

The power supply 90 applies voltage V1 to generate the electric fields105 in the epitaxial layer 10, and the electrons 70 are moved close tothe electrode Collector0 and the electrode Mix0 by the electric field105. Electrons 80 moved close to the electrode Collector0 and theelectrode Mix0 are pulled into the n-type diffusion layer 40, to whichthe power supply 100 applies voltage V2, and an electric current I0 isgenerated. Alternating the polarity of the power supply 90 in frequencyf (Hz) makes it possible to attain a demodulation effect necessary tomeasure distance. When the polarity of the power supply 90 is reversedfrom the state of FIG. 1, the electrons 70 are moved close to theelectrode Collector0 and the electrode Mix1 by the electric fields 105.Electrons moved close to the electrode Collector1 and the electrode Mix1are pulled into the n-type diffusion layer 50, to which the power supply100 applies voltage V2, and an electric current I1 is generated.

FIG. 2 is a schematic diagram illustrating both the schematiccross-sectional view illustrated in FIG. 1 and a top plan view of theToF sensor 1000. As illustrated in FIG. 2, as an example, the p-typediffusion layer 20, the p-type diffusion layer 30, the n-type diffusionlayer 40, and the n-type diffusion layer 50 all have rectangular planeshapes.

The technology of collectively treating a plurality of adjacent pixelsin the pixel array of an image sensor to virtually increase the lightreception area per pixel and increase the light reception sensitivity isreferred to as pixel combination or pixel binning. In the distancemeasurement system that uses the ToF sensor 1000, performing pixelcombination allows for increase in the light reception sensitivity, andmakes it possible to improve the distance measurement accuracy.Specifically, performing pixel combination enlarges the regions to whichthe power supply 90 applies the voltage V1, and increases the area inwhich the electrons 70 that are excited by the light 60 are present.Accordingly, it is possible to increase the light reception sensitivity.

Thus, in the system that uses the ToF sensor 1000, a target is floodlitwith light such as infrared light, and the light is received from thetarget to measure the distance to the target with the phase difference.At this time, performing pixel combination makes it possible toefficiently collect more electric charges.

FIG. 3 is a plan view illustrating an example in which two pixels arecombined in the case where pixel combination is performed with CAPDpixels. In FIG. 3, a pixel 110 and a pixel 120 adjacent to the rightthereof are connected to the respective electrodes, thereby making itpossible to virtually configure a large pixel. In more detail, theelectrode Mix0 is connected to the respective p-type diffusion layers 20of the pixel 110 and the pixel 120, and the electrode Mix1 is connectedto the respective p-type diffusion layers 30 of the pixel 110 and thepixel 120. In addition, the electrode Collector0 is connected to therespective n-type diffusion layers 40 of the pixel 110 and the pixel120, and the electrode Collector1 is connected to the respective n-typediffusion layers 50 of the pixel 110 and the pixel 120. According to theconfiguration illustrated in FIG. 3, the p-type diffusion layers 20, thep-type diffusion layers 30, the n-type diffusion layers 40, and then-type diffusion layers 50 are coupled in the pixel 110 and the pixel120, so that it is possible to combine the two pixels.

In addition, according to the principle of CAPD, electrons excited bylight are moved by electric fields. Therefore, different from FIG. 3, atechnique is used. In addition, voltage is applied to only one of theadjacent pixels, thereby making possible to combine the pixels. FIG. 4is a plan view illustrating an example in which, in the pixel 110 andthe pixel 120, which are adjacent to each other, voltage is applied tothe p-type diffusion layers 20 and 30 of the pixel 110, and, in a pixel130 and a pixel 140, which are adjacent to each other, voltage isapplied to the p-type diffusion layers 20 and 30 of the pixel 130.

As illustrated in FIG. 4, applying voltage to only one of the pixelsmakes it possible to enlarge the pixel. In this case, when focus isplaced on the pixel 130, in the pixel 120 and the pixel 140, which areadjacent to each other, no voltage is applied to the p-type diffusionlayers 20 or p-type diffusion 30. However, it is possible to collect theelectric charges within the range of an equivalent pixel region 210 fromthe p-type diffusion layer 20 and the p-type diffusion layer 30 of thepixel 130 by the electric fields 105 generated by the applied voltage.If the vertical and horizontal pitches of pixels are configured likeFIG. 3, the equivalent pixel region 210 has the same area as the area ofthe two of the pixel 110 and the pixel 120, which are combined accordingto the pixel combination described in FIG. 3. In FIG. 4, voltage justhas to be applied to the electrodes Mix0 and Mix1 of one pixel 130 toproduce electric fields in the equivalent pixel region 210 correspondingto two pixels. Meanwhile, in FIG. 3, more electric power is consumed toapply voltage to the electrodes Mix0 and Mix1 of the two pixels 110 and120 to produce electric fields in the region corresponding to two pixelsthan in FIG. 4. Thus, according to the configuration illustrated in FIG.4, the paths of the electric currents of the electrodes Mix0 and Mix1that produce electric fields to collect the electric charges of the samepixel region as that of FIG. 3 decrease from two to one. Accordingly, itis possible to make the electric power consumption less than the pixelcombination according to FIG. 3 does.

In FIG. 4, regarding the pixel 120 and the pixel 140, in which novoltage is applied to the p-type diffusion layers 20 and 30, voltagedoes not have to be applied to the n-type diffusion layers 40 and 50.Meanwhile, the n-type diffusion layers 40 and 50 of the pixel 120 andthe pixel 140 may be provided with any electric potential. For example,when the n-type diffusion layers 40 and 50 of the pixel 120 and thepixel 140 are provided with the same electric potential as that of theepitaxial layers 10, it is easier for the excited electrons 70 to gatherin the n-type diffusion layers 40 and 50 of the pixels 110 and 130through the electric fields 105. Note that, in FIG. 4, the descriptionhas been made with vertically long pixels used as an example, but squarepixels or horizontally long pixels may also be used.

Meanwhile, in the case where voltage is applied to the p-type diffusionlayers 20 and the p-type diffusion layers 30 of all the pixel 110, pixel120, pixel 130, and pixel 140 without performing pixel combination,electric power consumption increases, but it is possible to increaseresolution. Thus, it is desirable to drive all the pixels in the casewhere resolution is necessary, and perform pixel combination in the casewhere light reception sensitivity is increased. It is possible to decidewhether to drive all the pixels or perform pixel combination, inaccordance with the usage environment of the ToF sensor 1000, or thecondition, nature, or the like of a target that is to be floodlit withlight.

2. Example of Pixel Combination according to Present Embodiment

FIG. 5 is a plan view illustrating pixel combination according to thepresent embodiment. In FIG. 5, in the pixel 110 and the pixel 120, whichare combined, voltage is applied to the two of the p-type diffusionlayers 20 a and the p-type diffusion layers 30 a, which are diagonallypositioned in the pixel regions and the most distant, and the electricfields 105 are produced in an oblique direction of the arrangementdirection of the pixels to accumulate the electric charges. In this way,a long distance is secured between the pair of the p-type diffusionlayer 20 a and a p-type diffusion layer 30 b and the electric fields 105are provided within a wide range, so that it is possible to efficientlyaccumulate electric charges. The pair of the p-type diffusion layer 20 aand the p-type diffusion layer 30 a do not have to be positioneddiagonally, and may be any pair of p-type diffusion layers.

In the configuration illustrated in FIG. 4, the voltage V1 is applied tothe p-type diffusion layers 20 and 30 of one (pixel 110 and pixel 130)of two adjacent pixels. Accordingly, in the pixel 120 and pixel 140, thep-type diffusion layers 20 and 30 of which the voltage V1 is not appliedto, the electric fields 105 are not produced, but the electric fields105 are biased in the pixel regions. It is not possible to uniform theelectric fields 105 in the pixel regions. Meanwhile, in the presentembodiment illustrated in FIG. 5, a long distance is secured between thep-type diffusion layer 20 a and the p-type diffusion layer 30 a and itis possible to provide the electric fields 105 within a wide range, sothat resistance values increase to make it possible to decrease theelectric power consumption. Further, it is possible to uniformly producethe electric fields 105 in the pixel regions, so that it is possible toefficiently collect electrons excited in the regions.

FIGS. 6A to 6C are plan views each of which illustrates a variation ofthe arrangement of pixels. FIG. 6A illustrates the arrangement in whichthe arrangement of adjacent pixels is shifted by a half pixel in thevertical direction of the figure. According to the arrangementillustrated in FIG. 6A, it is possible to increase the area of regionscapable of contributing to the collection of electric charges when theelectric fields 105 are produced. In addition, according to theconfiguration illustrated in FIG. 6A, the electric fields 105 ofadjacent pixels are spaced apart from each other, so that it is possibleto suppress the generation of crosstalk. In this case, the pixels mayalso be vertically long, square, or horizontally long.

FIG. 6B is a schematic diagram illustrating an example in which pixelsare arranged in a grid. According to the configuration illustrated inFIG. 6B, the electric fields 105 of any pixel repel the electric fields105 of an adjacent pixel, and the electric fields do not expand around.Accordingly, it is not possible to enlarge the area of the regionscapable of contributing to the collection of electric charges. Thus, itis possible to enlarge regions capable of contributing to the collectionof electric charges in the arrangement illustrated in FIG. 6A ratherthan the arrangement illustrated in FIG. 6B.

FIG. 6C is a schematic diagram illustrating the case where pixelcombination is performed in the arrangement example of FIG. 6A. Asillustrated in FIG. 6C, applying voltage every other row from the p-typediffusion layers 20 and the p-type diffusion layers 30 makes it possibleto perform pixel combination.

FIG. 5 illustrates an example in which pixel combination is performed onthe regions (1×2-pixel region) including one pixel in the verticaldirection and two pixels in the horizontal direction, but it is alsopossible to combine pixel regions including any plurality of pixels.FIG. 7 is a schematic diagram illustrating an example in which pixelcombination is performed on a region (2×2-pixel region) that includestwo pixels in the vertical direction and two pixels in the horizontaldirection. In this case, voltage is applied between a p-type diffusionlayer 20 b of the pixel 110 and the p-type diffusion layer 30 b of thepixel 140 illustrated in FIG. 7 to produce the electric fields 105. Thismakes it possible to perform pixel combination on the regions of fourpixels which include two pixels in the vertical direction and two pixelsin the horizontal direction.

3. Regarding Driving of Pixel

FIG. 8 is a schematic diagram for describing the driving of a pixel. Atthe time of pixel combination, pixels are produced that are driven byapplying voltage to the p-type diffusion layers 20 and 30, and pixelsare produced that are not driven with no voltage applied to the p-typediffusion layers 20 and 30. Therefore, the ToF sensor 1000 is configuredto divide a drive line into a plurality of drive lines. As illustratedin FIG. 8, a power supply 90 a is connected to the p-type diffusionlayers 20 and the p-type diffusion layers 30 of the pixels 110 and 130.Meanwhile, a power supply 90 b is connected to the p-type diffusionlayers 20 and the p-type diffusion layers 30 of the pixels 120 and 140.At the time of pixel combination, the power supply 90 a is driven toapply the voltage V1 to electrodes Mix0 a and Mix1 a respectivelyconnected to the p-type diffusion layers 20 and 30 of the pixels 110 and130. Meanwhile, the power supply 90 b is not driven, thereby applying novoltage V to electrodes Mix0 b and Mix1 b respectively connected to thep-type diffusion layers 20 and 30 of the pixels 110 and 130. Thisproduces the electric fields 105 between the p-type diffusion layer 20and the p-type diffusion layer 30 of the pixel 110, and produces theelectric fields 105 between the p-type diffusion layer 20 and the p-typediffusion layer 30 of the pixel 130, so that the pixels are combinedsimilarly to FIG. 4.

In addition, in the case where pixel combination is not performed inFIG. 8, the power supply 90 a is driven to apply the voltage V1 to theelectrodes Mix0 a and Mix1 a, and the power supply 90 b is also drivento apply the voltage V1 to the electrodes Mix0 b and Mix1 b. In thisway, at the time of driving all the pixels when pixel combination is notperformed, providing the same driving signals to all the pixels makes itpossible to drive all the pixels.

As described above, at the time of pixel combination, the electrodesMix0 a and Mix1 a, which are driven, are distinguished from theelectrodes Mix0 b and Mix1 b, which are not driven, thereby making itpossible to set pixels that are driven by applying voltage and pixelsthat are not driven with no voltage applied.

FIG. 9 is a schematic diagram for describing the driving of a pixel, andillustrates the configuration of the case where electrodes diagonallypositioned in two adjacent pixels are driven. As illustrated in FIG. 9,the electrode Mix0 a of the power supply 90 a is connected to respectivep-type diffusion layers 20 c of the pixel 110 and the pixel 130. Inaddition, an electrode Mix1 a of the power supply 90 a is connected torespective p-type diffusion layers 30 c of the pixels 120 and 140. Inaddition, the electrode Mix0 b of the power supply 90 b is connected tothe respective p-type diffusion layers 20 of the pixel 120 and the pixel140, and the electrode Mix1 b of the power supply 90 b is connected tothe respective p-type diffusion layers 30 of the pixel 110 and the pixel130. At the time of pixel combination, the power supply 90 a is drivento apply the voltage V1 to the electrode Mix0 a connected to the pixels110 and 130 and the electrode Mix1 a connected to the pixels 120 and140. In addition, at the time of pixel combination, the power supply 90b is not driven, thereby applying no voltage V1 to the electrode Mix0 bconnected to the pixels 120 and 140 and the electrode Mix1 b connectedto the pixels 110 and 130. Thus, at the time of pixel combination, asillustrated in FIG. 9, the voltage V1 is applied between the p-typediffusion layer 20 c of the pixel 110 and the p-type diffusion layer 30c of the pixel 120, and the voltage V1 is applied between the p-typediffusion layer 20 c of the pixel 130 and the p-type diffusion layer 30c of the pixel 140. Accordingly, it is possible to produce the electricfields 105 in an oblique direction in the two of the adjacent pixels 110and 120, and produce the electric fields 105 in the oblique direction inthe two of the adjacent pixels 130 and 140.

In addition, in the case where pixel combination is not performed inFIG. 9, the power supply 90 a and the power supply 90 b are both drivento apply the voltage V1 to the electrode Mix0 a and the electrode Mix1 aand also apply the voltage V1 to the electrode Mix1 b. In this way, atthe time of driving all the pixels when pixel combination is notperformed, providing the same driving signals to all the pixels makes itpossible to drive all the pixels.

FIG. 10 is a schematic diagram illustrating an example in which switches160, 162, 164, and 166 are provided to connect the electrode Mix0 to thep-type diffusion layers 20 of the pixel 110, the pixel 120, the pixel130 and the pixel 140, connect the electrode Mix1 to the p-typediffusion layers 30 of the pixel 110, the pixel 120, the pixel 130 andthe pixel 140, and produce the electric fields 105 in the obliquedirection, which are similar to those of FIG. 9, at the time of pixelcombination. In the case where pixel combination is performed, asillustrated in FIG. 10, the switches 160, 162, 164, and 166 are turnedoff and the power supply 90 is driven to apply the voltage V1 to ap-type diffusion layer 20 d of the pixel 110, a p-type diffusion layer30 d of the pixel 120, the p-type diffusion layer 20 d of the pixel 130,and the p-type diffusion layer 30 d of a pixel 140 d. In addition, inthe case where pixel combination is not performed, all the switches 160,162, 164, and 166 are turned on and the voltage V1 is applied from thepower supply 90 to the p-type diffusion layers 20 and the p-typediffusion layers 30 of all the pixels to drive all the pixel 110, thepixel 120, the pixel 130, and the pixel 140. Note that the switches 160,162, 164, and 166 can be implemented, for example, by field effecttransistors (MOSFET) or the like.

4. Configuration Example of Distance Measurement System According toPresent Embodiment

FIG. 11 is a schematic diagram illustrating the configuration of adistance measurement system 2000 including the ToF sensor 1000 that isan imaging apparatus according to the present embodiment. As illustratedin FIG. 11, the distance measurement system 2000 includes the ToF sensor1000, an infrared light floodlighting apparatus 1100 that floodlightsthe target 1300 with infrared light, and a control apparatus 2000 thatcontrols the ToF sensor 1000 and the infrared light floodlightingapparatus 1100. The infrared light floodlighting apparatus 1100floodlights the target 1300 with infrared light 1110, and the light 60reflected by the target 1300 is incident on the ToF sensor 1000, therebydetecting the light 60. A control apparatus 1200 synchronizes theinfrared light floodlighting apparatus 1100 with the imaging apparatus1000, and acquires the time at which the infrared light floodlightingapparatus 1100 casts the infrared light 1110 and the time at which theToF sensor 1000 receives the light 60. The control apparatus 1200 thenmeasures the distance to the target 130 on the basis of the period oftime (time of flight) from the time at which the infrared light 1110 iscast to the time at which the ToF sensor 1000 receives the light 60.

5. Application Examples

The technology according to the present disclosure is applicable to avariety of products. For example, the technology according to thepresent disclosure is implemented as apparatuses mounted on any type ofmobile objects such as automobiles, electric vehicles, hybrid electricvehicles, motorcycles, bicycles, personal mobilities, airplanes, drones,ships, robots, construction machines, and agricultural machines(tractors).

FIG. 12 is a block diagram illustrating a schematic configurationexample of a vehicle control system 7000 that is an example of a mobileobject control system to which the technology according to the presentdisclosure can be applied. The vehicle control system 7000 includes aplurality of electronic control units connected via a communicationnetwork 7010. In the example illustrated in FIG. 12, the vehicle controlsystem 7000 includes a drive line control unit 7100, a body systemcontrol unit 7200, a battery control unit 7300, a vehicle outsideinformation detecting unit 7400, a vehicle inside information detectingunit 7500, and an integrated control unit 7600. The communicationnetwork 7010, which connects the plurality of these control units, maybe an in-vehicle communication network such as a controller area network(CAN), a local interconnect network (LIN), a local area network (LAN),or FlexRay (registered trademark) that is compliant with any standard.

Each control unit includes a microcomputer that performs operationprocessing in accordance with a variety of programs, a storage sectionthat stores the programs, parameters used for the variety of operations,or the like executed by the microcomputer, and a driving circuit thatdrives apparatuses subjected to various types of control. Each controlunit includes a network I/F used to communicate with the other controlunits via the communication network 7010, and a communication I/F usedto communicate with apparatuses, sensors, or the like outside and insidethe vehicle through wired communication or wireless communication. FIG.12 illustrates a microcomputer 7610, a general-purpose communication I/F7620, a dedicated communication I/F 7630, a positioning section 7640, abeacon receiving section 7650, an onboard apparatus I/F 7660, a soundand image output section 7670, an in-vehicle network I/F 7680, and astorage section 7690 as functional components of the integrated controlunit 7600. Each of the other control units similarly includes amicrocomputer, a communication I/F, a storage section, and the like.

The drive line control unit 7100 controls the operation of apparatusrelated to the drive line of the vehicle in accordance with a variety ofprograms. For example, the drive line control unit 7100 functions as acontrol apparatus for a driving force generating apparatus such as aninternal combustion engine or a driving motor that generates the drivingforce of the vehicle, a driving force transferring mechanism thattransfers the driving force to wheels, a steering mechanism that adjuststhe steering angle of the vehicle, a braking apparatus that generatesthe braking force of the vehicle, and the like. The drive line controlunit 7100 may have the function of a control apparatus for an antilockbrake system (ABS) or an electronic stability control (ESC).

The drive line control unit 7100 is connected to a vehicle statedetecting section 7110. The vehicle state detecting section 7110includes, for example, at least one of sensors such as a gyro sensorthat detects the angular velocity of the axial rotating motion of thevehicle body, an acceleration sensor that detects the acceleration ofthe vehicle, or a sensor that detects the operation amount of theaccelerator pedal, the operation amount of the brake pedal, the steeringwheel angle of the steering wheel, the engine speed, the wheel rotationspeed, or the like. The drive line control unit 7100 uses a signal inputfrom the vehicle state detecting section 7110 to perform operationprocessing, and controls the internal combustion engine, the drivingmotors, the electric power steering apparatus, the braking apparatus, orthe like.

The body system control unit 7200 controls the operations of a varietyof apparatuses attached to the vehicle body in accordance with a varietyof programs. For example, the body system control unit 7200 functions asa control apparatus for a keyless entry system, a smart key system, apower window apparatus, or a variety of lights such as a headlight, abackup light, a brake light, a blinker, or a fog lamp. In this case, thebody system control unit 7200 can receive radio waves transmitted from aportable apparatus that serves instead of the key or signals of avariety of switches. The body system control unit 7200 receives theseradio waves or signals, and controls the vehicle door lock apparatus,the power window apparatus, the lights, or the like.

The battery control unit 7300 controls a secondary battery 7310 inaccordance with a variety of programs. The secondary battery 7310 servesas a power supply source of a driving motor. For example, the batterycontrol unit 7300 receives information such as the battery temperature,the battery output voltage, or the remaining battery capacity from abattery apparatus including the secondary battery 7310. The batterycontrol unit 7300 uses these signals to perform operation processing,and performs temperature adjusting control on the secondary battery 7310or controls a cooling apparatus or the like included in the batteryapparatus.

The vehicle outside information detecting unit 7400 detects informationregarding the outside of the vehicle including the vehicle controlsystem 7000. For example, the vehicle outside information detecting unit7400 is connected to at least one of an imaging section 7410 and avehicle outside information detecting section 7420. The imaging section7410 includes at least one of a time of flight (ToF) camera, a stereocamera, a monocular camera, an infrared camera, and other cameras. Thevehicle outside information detecting section 7420 includes, forexample, at least one of an environment sensor that detects the currentweather, and a surrounding information detecting sensor that detectsanother vehicle, an obstacle, a pedestrian, or the like around thevehicle including the vehicle control system 7000.

The environment sensor may be, for example, at least one of a raindropsensor that detects rainy weather, a fog sensor that detects a fog, asunshine sensor that detects the degree of sunshine, a snow sensor thatdetects a snowfall. The surrounding information detecting sensor may beat least one of an ultrasonic sensor, a radar apparatus, and a lightdetection and ranging/laser imaging detection and ranging (LIDAR)apparatus. These imaging section 7410 and vehicle outside informationdetecting section 7420 may be installed as independent sensors orapparatuses, or as an apparatus into which sensors and apparatuses areintegrated.

Here, FIG. 13 illustrates an example of the installation positions ofthe imaging section 7410 and the vehicle outside information detectingsection 7420. Imaging sections 7910, 7912, 7914, 7916, and 7918 arepositioned, for example, at at least one of the front nose, a sidemirror, the rear bumper, the back door, and the upper part of thewindshield in the vehicle compartment of a vehicle 7900. The imagingsection 7910 attached to the front nose and the imaging section 7918attached to the upper part of the windshield in the vehicle compartmentchiefly acquire images of the area ahead of the vehicle 7900. Theimaging sections 7912 and 7914 attached to the side mirrors chieflyacquire images of the areas on the sides of the vehicle 7900. Theimaging section 7916 attached to the rear bumper or the back doorchiefly acquires images of the area behind the vehicle 7900. The imagingsection 7918 attached to the upper part of the windshield in the vehiclecompartment is used chiefly to detect a preceding vehicle, a pedestrian,an obstacle, a traffic light, a traffic sign, a lane, or the like.

Note that FIG. 13 illustrates an example of the respective imagingranges of the imaging sections 7910, 7912, 7914, and 7916. An imagingrange a represents the imaging range of the imaging section 7910attached to the front nose. Imaging ranges b and c respectivelyrepresent the imaging ranges of the imaging sections 7912 and 7914attached to the side mirrors. An imaging range d represents the imagingrange of the imaging section 7916 attached to the rear bumper or theback door. For example, overlaying image data captured by the imagingsections 7910, 7912, 7914, and 7916 offers an overhead image that looksdown on the vehicle 7900.

Vehicle outside information detecting sections 7920, 7922, 7924, 7926,7928, and 7930 attached to the front, the rear, the sides, the corners,and the upper part of the windshield in the vehicle compartment of thevehicle 7900 may be, for example, ultrasonic sensors or radarapparatuses. The vehicle outside information detecting sections 7920,7926, and 7930 attached to the front nose, the rear bumper, the backdoor, and the upper part of the windshield in the vehicle compartment ofthe vehicle 7900 may be, for example, LIDAR apparatuses. These vehicleoutside information detecting sections 7920 to 7930 are used chiefly todetect a preceding vehicle, a pedestrian, an obstacle, or the like.

The description will continue with reference to FIG. 12 again. Thevehicle outside information detecting unit 7400 causes the imagingsection 7410 to capture images of the outside of the vehicle, andreceives the captured image data. In addition, the vehicle outsideinformation detecting unit 7400 receives detection information from theconnected vehicle outside information detecting section 7420. In thecase where the vehicle outside information detecting section 7420 is anultrasonic sensor, a radar apparatus, or a LIDAR apparatus, the vehicleoutside information detecting unit 7400 causes ultrasound, radio waves,or the like to be transmitted, and receives the information of thereceived reflected waves. The vehicle outside information detecting unit7400 may perform processing of detecting an object such as a person, acar, an obstacle, a traffic sign, or a letter on a road, or a process ofdetecting the distance on the basis of the received information. Thevehicle outside information detecting unit 7400 may perform environmentrecognition processing of recognizing a rainfall, a fog, a roadcondition, or the like on the basis of the received information. Thevehicle outside information detecting unit 7400 may compute the distanceto an object outside the vehicle on the basis of the receivedinformation.

Further, the vehicle outside information detecting unit 7400 may performimage recognition processing of recognizing a person, a car, anobstacle, a traffic sign, a letter on a road, or the like, or processingof detecting the distance on the basis of the received image data. Thevehicle outside information detecting unit 7400 may perform distortioncorrecting processing, positioning processing, or the like on thereceived image data, and combine image data captured by a differentimaging section 7410 to generate an overhead view or a panoramic image.The vehicle outside information detecting unit 7400 may use the imagedata captured by the other imaging section 7410 to perform viewpointconverting processing.

The vehicle inside information detecting unit 7500 detects informationregarding the inside of the vehicle. The vehicle inside informationdetecting unit 7500 is connected, for example, to a driver statedetecting section 7510 that detects the state of the driver. The driverstate detecting section 7510 may include a camera that images thedriver, a biological sensor that detects biological information of thedriver, a microphone that picks up a sound in the vehicle compartment,or the like. The biological sensor is attached, for example, to aseating face, the steering wheel, or the like, and detects biologicalinformation of the passenger sitting on the seat or the driver grippingthe steering wheel. The vehicle inside information detecting unit 7500may compute the degree of the driver's tiredness or the degree of thedriver's concentration or determine whether the driver have a doze, onthe basis of detection information input from the driver state detectingsection 7510. The vehicle inside information detecting unit 7500 mayperform processing such as noise cancelling processing on the picked-upsound signal.

The integrated control unit 7600 controls the overall operation insidethe vehicle control system 7000 in accordance with a variety ofprograms. The integrated control unit 7600 is connected to an inputsection 7800. The input section 7800 is implemented as an apparatus, forexample, a touch panel, a button, a microphone, a switch, a lever, orthe like on which a passenger can perform an input operation. Theintegrated control unit 7600 may receive data obtained by recognizingthe voice input through the microphone. The input section 7800 may be,for example, a remote control apparatus that uses infrared light orother radio waves, or an external connection apparatus such as a mobiletelephone or a personal digital assistant (PDA) corresponding to theoperation of the vehicle control system 7000. The input section 7800 maybe, for example, a camera. In that case, a passenger can inputinformation through gesture. Alternatively, data may be input that isobtained by detecting the movement of a wearable apparatus worn by apassenger. Moreover, the input section 7800 may include an input controlcircuit or the like that generates an input signal, for example, on thebasis of information input by a passenger or the like using theabove-described input section 7800, and outputs the generated inputsignal to the integrated control unit 7600. The passenger or the likeoperates this input section 7800, thereby inputting various types ofdata to the vehicle control system 7000 or instructing the vehiclecontrol system 7000 about a processing operation.

The storage section 7690 may include a read only memory (ROM) thatstores a variety of programs to be executed by a microcomputer, and arandom access memory (RAM) that stores a variety of parameters,operation results, sensor values, or the like. In addition, the storagesection 7690 may be implemented by a magnetic storage device such as ahard disk drive (HDD), a semiconductor storage device, an opticalstorage device, a magneto-optical storage device, or the like.

The general-purpose communication I/F 7620 is a general-purposecommunication I/F that mediates in communication between a variety ofapparatuses in an external environment 7750. The general-purposecommunication I/F 7620 may implement a cellular communication protocolsuch as Global System of Mobile communications (GSM (registeredtrademark)), WiMAX, Long Term Evolution (LTE) or LTE-Advanced (LTE-A),or other wireless communication protocols such as a wireless LAN (whichis also referred to as Wi-Fi (registered trademark)) or Bluetooth(registered trademark). The general-purpose communication I/F 7620 maybe connected to an apparatus (such as an application server or a controlserver) on an external network (such as the Internet, a cloud network,or a network specific to a service provider), for example, via a basestation or an access point. In addition, the general-purposecommunication I/F 7620 may be connected to a terminal (such as aterminal of the driver, a pedestrian or a store, or a machine typecommunication (MTC) terminal) in the vicinity of the vehicle, forexample, using the peer-to-peer (P2P) technology.

The dedicated communication I/F 7630 is a communication I/F thatsupports a communication protocol defined for the purpose of use forvehicles. The dedicated communication I/F 7630 may implement a standardprotocol, for example, wireless access in vehicle environment (WAVE),which is a combination of IEEE 802.11p for the lower layer and IEEE 1609for the upper layer, dedicated short range communications (DSRC), or acellular communication protocol. The dedicated communication I/F 7630typically performs V2X communication. The V2X communication is a conceptincluding one or more of vehicle-to-vehicle communication,vehicle-to-infrastructure communication, vehicle-to-home communication,and vehicle-to-pedestrian communication.

The positioning section 7640 receives, for example, global navigationsatellite system (GNSS) signals (such as global positioning system (GPS)signals from a GPS satellite) from a GNSS satellite for positioning, andgenerates position information including the latitude, longitude, andaltitude of the vehicle. Note that the positioning section 7640 may alsoidentify the present position by exchanging signals with a wirelessaccess point, or acquire position information from a terminal such as amobile phone, a PHS, or a smartphone that has a positioning function.

The beacon receiving section 7650 receives radio waves orelectromagnetic waves, for example, from a wireless station or the likeinstalled on the road, and acquires information such as the presentposition, traffic congestion, closed roads, or necessary time. Note thatthe function of the beacon receiving section 7650 may be included in theabove-described dedicated communication I/F 7630.

The onboard apparatus I/F 7660 is a communication interface thatmediates in connections between the microcomputer 7610 and a variety ofonboard apparatuses 7760 in the vehicle. The onboard apparatus I/F 7660may use a wireless communication protocol such as a wireless LAN,Bluetooth (registered trademark), near field communication (NFC), or awireless USB (WUSB) to establish a wireless connection. In addition, theonboard apparatus I/F 7660 may also establish a wired connection such asa universal serial bus (USB), a high-definition multimedia interface(HDMI (registered trademark)), or a mobile high-definition link (MHL)via a connection terminal (not illustrated) (and a cable if necessary).The onboard apparatuses 7760 may include, for example, at least one of amobile apparatus of a passenger, a wearable apparatus of a passenger,and an information apparatus carried into or attached to the vehicle. Inaddition, the onboard apparatuses 7760 may also include a navigationapparatus that searches for routes to any destination. The onboardapparatus I/F 7660 exchanges control signals or data signals with theseonboard apparatuses 7760.

The in-vehicle network I/F 7680 is an interface that mediates incommunication between the microcomputer 7610 and the communicationnetwork 7010. The in-vehicle network I/F 7680 transmits and receivessignals or the like in compliance with a predetermined protocolsupported by the communication network 7010.

The microcomputer 7610 of the integrated control unit 7600 controls thevehicle control system 7000 in accordance with a variety of programs onthe basis of information acquired via at least one of thegeneral-purpose communication I/F 7620, the dedicated communication I/F7630, the positioning section 7640, the beacon receiving section 7650,the onboard apparatus I/F 7660, and the in-vehicle network I/F 7680. Forexample, the microcomputer 7610 may calculate a control target value ofthe driving force generating apparatus, the steering mechanism, or thebraking apparatus on the basis of acquired information regarding theinside and outside of the vehicle, and output a control instruction tothe drive line control unit 7100. For example, the microcomputer 7610may perform cooperative control for the purpose of executing thefunctions of an advanced driver assistance system (ADAS) includingvehicle collision avoidance or impact reduction, follow-up driving basedon the inter-vehicle distance, constant vehicle speed driving, vehiclecollision warning, vehicle lane departure warning, or the like. Inaddition, the microcomputer 7610 may control the driving forcegenerating apparatus, the steering mechanism, the braking apparatus, orthe like on the basis of acquired information regarding the areas aroundthe vehicle, thereby performing cooperative control for the purpose ofautomatic driving or the like that allows the vehicle to autonomouslytravel irrespective of any operation of a driver.

The microcomputer 7610 may generate three-dimensional distanceinformation regarding the distance between the vehicle and an objectsuch as a nearby structure or person on the basis of informationacquired via at least one of the general-purpose communication I/F 7620,the dedicated communication I/F 7630, the positioning section 7640, thebeacon receiving section 7650, the onboard apparatus I/F 7660, and thein-vehicle network I/F 7680, and create local map information includingsurrounding information regarding the present position of the vehicle.Further, the microcomputer 7610 may predict danger such as vehiclecollisions, approaching pedestrians or the like, or entry to closedroads on the basis of acquired information, and generate a warningsignal. The warning signal may be, for example, a signal used togenerate a warning sound or turn on the warning lamp.

The sound and image output section 7670 transmits an output signal of atleast one of sound and images to an output apparatus capable of visuallyor aurally notifying a passenger of the vehicle or the outside of thevehicle of information. In the example of FIG. 12, an audio speaker7710, a display section 7720, and an instrument panel 7730 areexemplified as the output apparatus. For example, the display section7720 may include at least one of an onboard display and a head-updisplay. The display section 7720 may have an augmented reality (AR)display function. The output apparatus may also be an apparatus otherthan these apparatuses like a headphone, a wearable apparatus such as aglasses-type display worn by a passenger, a projector, or a lamp. In thecase where the output apparatus is a display apparatus, the displayapparatus visually displays a result obtained by the microcomputer 7610performing a variety of processes or information received from anothercontrol unit in a variety of forms such as text, images, tables, orgraphs. In addition, in the case where the output apparatus is a soundoutput apparatus, the sound output apparatus converts sound signalsincluding reproduced sound data, acoustic data, or the like into analogsignals, and aurally outputs the analog signals.

Note that, in the example illustrated in FIG. 12, at least two controlunits connected via the communication network 7010 may be integratedinto one control unit. Alternatively, the individual control units maybe configured as a plurality of control units. Moreover, the vehiclecontrol system 7000 may also include another control unit that is notillustrated. Further, a part or the whole of the functions executed byany of the control units may be executed by another control unit in theabove description. That is, as long as information is transmitted andreceived via the communication network 7010, predetermined operationprocessing may be performed by any of the control units. Similarly, asensor or an apparatus connected to any of the control units may beconnected to another control unit, and the control units may transmitand receive detection information to and from each other via thecommunication network 7010.

Note that the distance measurement unit 2000 according to the presentembodiment is configured, for example, as the imaging section 7410illustrated in FIG. 12. The vehicle outside information detecting unit7400 detects the distance to the target 130 outside the vehicle, whichis measured by the distance measurement unit 2000, as vehicle outsideinformation.

In addition, the distance measurement unit 2000 according to the presentembodiment is configured, for example, as the driver state detectingsection 7510 illustrated in FIG. 12. The vehicle inside informationdetecting unit 7500 detects the distance to the target 130 inside thevehicle, which is measured by the distance measurement unit 2000, asvehicle inside information. Examples of the target 130 inside thevehicle include a driver of an automobile or the like. In this case, thevehicle inside information detecting unit 7500 is capable of detectinginformation of the driver.

The preferred embodiment(s) of the present disclosure has/have beendescribed above with reference to the accompanying drawings, whilst thepresent disclosure is not limited to the above examples. A personskilled in the art may find various alterations and modifications withinthe scope of the appended claims, and it should be understood that theywill naturally come under the technical scope of the present disclosure.

Further, the effects described in this specification are merelyillustrative or exemplified effects, and are not limitative. That is,with or in the place of the above effects, the technology according tothe present disclosure may achieve other effects that are clear to thoseskilled in the art from the description of this specification.

Additionally, the present technology may also be configured as below.

(1) An imaging apparatus including:

-   -   a pair of electric field application electrodes and a pair of        electric charge extraction electrodes provided to each of a        plurality of pixels; and    -   a voltage application section configured to apply voltage        between a first electrode that is one of the pair of electric        field application electrodes of a first pixel and a second        electrode that is one of the pair of electric field application        electrodes of a second pixel when pixel combination is        performed, and produce an electric field across the first pixel        and the second pixel.

(2) The imaging apparatus according to (1), in which

-   -   in each of the plurality of pixels, the pair of electric field        application electrodes are disposed to be spaced apart in a        first direction,    -   the first pixel and the second pixel are disposed adjacent to        each other in a second direction orthogonal to the first        direction, and    -   the first electrode and the second electrode are positioned in a        diagonal direction of a region including the first pixel and the        second pixel.

(3) The imaging apparatus according to (1), in which

-   -   the first pixel and the second pixel are included in four pixels        disposed in a region including two pixels in a vertical        direction and two pixels in a horizontal direction, the first        pixel and the second pixel are positioned in a diagonal        direction of the region of the four pixels, and    -   the first electrode and the second electrode are electrodes that        are most distant in the diagonal direction of the region of the        four pixels among the pair of electric field application        electrodes included in each of the first pixel and the second        pixel.

(4) The imaging apparatus according to any of (1) to (3), in which

-   -   the voltage application section applies voltage between the        first electrode and the second electrode, the voltage being        reversed at predetermined frequency.

(5) The imaging apparatus according to (4), including:

-   -   a second voltage application section configured to apply, in a        case where pixel combination is not performed, voltage to a        third electrode that is another of the pair of electric field        application electrodes of the first pixel and a fourth electrode        that is another of the pair of electric field application        electrodes of the second pixel.

(6) The imaging apparatus according to (4), in which

-   -   the voltage application section includes        -   a power supply that applies, at time of driving all pixels            when pixel combination is not performed, voltage between the            pair of electric field application electrodes of the            plurality of pixels, and        -   a switch that separates, when pixel combination is            performed, part of a connection between the power supply and            the pair of electric field application electrodes, and            applies voltage between the first electrode and the second            electrode.

(7) The imaging apparatus according to any of (1) to (6), in which

-   -   an electric charge excited by received light is moved with        voltage applied to the pair of electric field application        electrodes and extracted with voltage applied to the pair of        electric charge extraction electrodes.

(8) A distance measurement system including:

-   -   a floodlight apparatus configured to floodlight a target with        light;    -   an imaging apparatus configured to receive light reflected by        the target; and    -   a control apparatus configured to control the floodlight        apparatus and the imaging apparatus, in which    -   the imaging apparatus includes        -   a pair of electric field application electrodes and a pair            of electric charge extraction electrodes provided to each of            a plurality of pixels, and        -   a voltage application section configured to apply voltage            between a first electrode that is one of the pair of            electric field application electrodes of a first pixel and a            second electrode that is one of the pair of electric field            application electrodes of a second pixel when pixel            combination is performed, and produce an electric field            across the first pixel and the second pixel.

REFERENCE SIGNS LIST

-   20, 30 p-type diffusion layer-   40, 50 n-type diffusion layer-   90, 90 a, 90 b power supply-   110, 120, 130, 140 pixel-   160, 162, 164, 166 switch-   1000 imaging apparatus-   1100 infrared light floodlighting apparatus-   1200 control apparatus-   2000 distance measurement system

The invention claimed is:
 1. An imaging apparatus comprising: a pair ofelectric field application electrodes and a pair of electric chargeextraction electrodes provided to each of a plurality of pixels; and avoltage application section configured to apply voltage between a firstelectrode that is one of the pair of electric field applicationelectrodes of a first pixel and a second electrode that is one of thepair of electric field application electrodes of a second pixel whenpixel combination is performed, and produce an electric field across thefirst pixel and the second pixel, wherein the voltage applicationsection is further configured to apply the voltage between the firstelectrode and the second electrode, the voltage being reversed at apredetermined frequency.
 2. The imaging apparatus according to claim 1,wherein in each of the plurality of pixels, the pair of electric fieldapplication electrodes are disposed to be spaced apart in a firstdirection, the first pixel and the second pixel are disposed adjacent toeach other in a second direction orthogonal to the first direction, andthe first electrode and the second electrode are positioned in adiagonal direction of a region including the first pixel and the secondpixel.
 3. The imaging apparatus according to claim 1, wherein the firstpixel and the second pixel are included in four pixels disposed in aregion including two pixels in a vertical direction and two pixels in ahorizontal direction, the first pixel and the second pixel arepositioned in a diagonal direction of the region of the four pixels, andthe first electrode and the second electrode are electrodes that aremost distant in the diagonal direction of the region of the four pixelsamong the pair of electric field application electrodes included in eachof the first pixel and the second pixel.
 4. The imaging apparatusaccording to claim 1, comprising: a second voltage application sectionconfigured to apply, in a case where pixel combination is not performed,voltage to a third electrode that is another of the pair of electricfield application electrodes of the first pixel and a fourth electrodethat is another of the pair of electric field application electrodes ofthe second pixel.
 5. The imaging apparatus according to claim 1, whereinthe voltage application section includes a power supply configured toapply, at time of driving all pixels when pixel combination is notperformed, voltage between the pair of electric field applicationelectrodes of the plurality of pixels, and a switch configured toseparate, when pixel combination is performed, part of a connectionbetween the power supply and the pair of electric field applicationelectrodes, and applies voltage between the first electrode and thesecond electrode.
 6. The imaging apparatus according to claim 1, whereinan electric charge excited by received light is moved with voltageapplied to the pair of electric field application electrodes andextracted with voltage applied to the pair of electric charge extractionelectrodes.
 7. A distance measurement system comprising: a floodlightapparatus configured to floodlight a target with light; an imagingapparatus configured to receive light reflected by the target; and acontrol apparatus configured to control the floodlight apparatus and theimaging apparatus, wherein the imaging apparatus includes a pair ofelectric field application electrodes and a pair of electric chargeextraction electrodes provided to each of a plurality of pixels, and avoltage application section configured to apply voltage between a firstelectrode that is one of the pair of electric field applicationelectrodes of a first pixel and a second electrode that is one of thepair of electric field application electrodes of a second pixel whenpixel combination is performed, and produce an electric field across thefirst pixel and the second pixel, wherein the voltage applicationsection is further configured to apply the voltage between the firstelectrode and the second electrode, the voltage being reversed at apredetermined frequency.